Objective: A relative resistance of immune cells to steroids has been established in patients with major depression (MD). In this study, we investigated the in vitro responsiveness of T cells to dexamethasone (DEX) of patients with bipolar disorder (BD). Methods: T cells of outpatients with DSM-IV BD (n = 54) and of healthy control subjects (HC; n = 29) were isolated, cultured and stimulated with phytohemagglutinin (PHA) for 72 h. The suppressive effect of graded concentrations of DEX (5 × 10 -9-10 -5 M) on PHA-induced CD25 (IL-2R) expression was measured by fluorescence-activated cell sorting (FACS) analysis. Data were correlated to the T-cell activation status in the peripheral blood of the same patients and to their diagnosis, current mood state, ultradian cycling pattern and current use of medication, including lithium. Results: T cells of patients with BD were less sensitive to DEX-induced suppressive effects as compared with T cells of HC. These data were particularly evident at 10 -7 M DEX (mean % suppression ± SEM BD: 18.9% ± 3.5 versus HC: 35.8% ± 4.7, p = 0.001). We found no correlations of this relative in vitro DEX resistance of T cells neither with the previously mentioned clinical characteristics nor with the actual activation status of the T cells in the BD patients. Conclusion: A relative T-cell resistance to steroids, as has been observed in MD previously, may be a trait phenomenon of BD, independent of mood state.

Bipolar disorder, Dexamethasone, Resistance, T cells
dx.doi.org/10.1111/j.1399-5618.2006.00359.x, hdl.handle.net/1765/65493
Bipolar Disorders (English Edition, Print)
Department of Immunology

Knijff, E.M, Breunis, W.B, van Geest, M.C, Kupka, R.W, Ruwhof, C, de Wit, H.J, … Drexhage, H.A. (2006). A relative resistance of T cells to dexamethasone in bipolar disorder. Bipolar Disorders (English Edition, Print), 8(6), 740–750. doi:10.1111/j.1399-5618.2006.00359.x